


Skin to Bone

by NollieBones



Category: Undertale (Video Game)
Genre: Accidental Voyeurism, Bad Puns, Big Sans, Biting, Body Worship, But not Bara!Sans, Cinnamon Roll Papyrus, Daddy Kink, Dirty Talk, Ecto-Penis, Ecto-Tongue, Eventual Feelings, F/M, Fluffy Ending, Foreplay, French Kissing, Grillby's, I Blame Tumblr, I Tried, I Wrote This Instead of Sleeping, Implied/Referenced Self-Harm, It gets rough then soft????, M/M, Masturbation, Mettaton EX, Nipple Play, Papyrus Being Papyrus, Reader Is Not Frisk, References to Depression, Self Confidence Issues, Slow Burn, Sorry guys, Soul Bond, Teasing, Teleportation, This Is Why We Can't Have Nice Things, Vaginal Fingering, You Have Been Warned, You blush a lot, You're a freak, You're really fucking quiet and it bothers me, cinnamon bunny, i can't write, so much sin
Language: English
Status: Completed
Published: 2016-05-15
Updated: 2016-05-15
Packaged: 2018-06-07 23:21:51
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,800
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6829507
Author URL: https://archiveofourown.org/users/NollieBones/pseuds/NollieBones
Summary: <blockquote class="userstuff">
              <p>In the blink of an eye (literally), you were pinned to the wall by Sans. There was a hunger in the way he scanned you; a craving. You better not be fucking dreaming.</p><p>“Kid, do you know how long I’ve wanted this? How long I’ve wanted <em>you</em>?” Sans’ voice dropped to a whisper in your ear, turning you on more. “I’ve been aching for ya to tug this bone.”</p><p>It came to your attention that his shorts were glowing, specifically the part where a penis is suppose to be. You were dead set on telling yourself this was a dream and it wasn’t happening. Sans would never go this far, would he?</p>
            </blockquote>





	Skin to Bone

**Author's Note:**

  * Inspired by [Burning Envy](https://archiveofourown.org/works/5486942) by [Marcanine](https://archiveofourown.org/users/Marcanine/pseuds/Marcanine). 
  * Inspired by [Taste](https://archiveofourown.org/works/6214987) by [Marcanine](https://archiveofourown.org/users/Marcanine/pseuds/Marcanine). 



You’re downstairs in the skele-bros house snacking on the Cinnamon Bunny you bought earlier and watching Mettaton’s newest cooking show, listening to him rave about spices, ingredients, and the importance of temperature. Papyrus isn’t home and Sans is in his room playing what sounds to be a trombone. Whether he actually carries interest in the instrument, has it for the sake of tormenting his brother, or because of the bone pun is beyond you.

That older skeleton drives you up the wall sometimes but you can’t help the feelings you’ve acquired for him. Since you moved into their - your - house months ago, Papyrus and Sans have been nothing but kind toward you, even going out of their way to see that you’re content with the living arrangements. Especially Sans; he’s been sending signals of a stronger relationship for a week. The longer you think of your fondness, the more a dusting of red frosts your cheeks.

Before you realize it, you’ve been lost in your thoughts for ten minutes and the two Cinnamon Bunnies you had are now perished. Mettaton is running back and forth across the screen snatching up all the elements for a cake now, making you only want _more_ food. A smile plasters itself on your lips as an idea pops into your head: Sans has all the junk food in his room. You wonder aloud if you can finally muster up the courage to tell Sans your adoration for him.

Halfway up the stairs, low groans can be heard resonating from his room. A notion lurched it’s way into the back of your mind - it sounded like sexual noises. The closer you got, the louder they became, almost as if he knew you were standing there and was begging to be heard.

“F-Fuuuuck…” He sighed desperately. This new tone of his made your heat moisten as you inched closer. It took everything in you not to crack the door open to peek in just out of curiosity. One little look wouldn’t hurt would it? After all, it’s probably not even Sa-

A cerulean color lit up the right corner of the room. The air was musty and smelled of fruit punch and ketchup. How original. Sans sat on his bed, covers still balled up in the middle, with headphones over his skull, his spine facing you. A laptop was in front of him that projected porn - a man choking a girl, to be matter-of-fact.

Your face set ablaze when you saw what he held in his boney palm - a thick, sky-blue cock that was massive in length. He was pumping his metacarpals slow, discreetly mewling over the content on the screen. A flame the same color as his cock licked the left side of his temporal bone, seeming to dance with the rhythm of his hand. You forced your thighs together as he sped up, a delirium sensation washing over you when he cried out from pleasure.

Realizing this is what illuminated the corner, you quickly shut the door and wheezed as you also realized you just watched him masturbate. God, you’re a freak!! And your fervid peach sending you into a mess of hormones doesn't help one bit. This could quite possibly be your only moment to act, and by the looks of it, you ought to hurry.

You inhaled sharply and thought out your plan of attack, pressing your back to the wall on the right of the door. You _could_ just… watch a few more seconds. Sans probably didn’t even notice you standing there. This idea was so terrifyingly erogenous that your lust got the better of you and you found yourself reaching for the door handle a second time. You hardly nudged the entrance before something - or someone - pulled the door back, staring directly in your eyes.

Your breath caught in your throat when you became acutely aware of exactly who this was. The guy you just fucking watching jerk himself. The guy _you_ masturbated about frequently. The guy who was sending you so many signs of this moment that it frightened you.

“D’you like what you saw?” Sans questioned in a hoarse tone, his perma-grin widening as you scrambled for a response.

“I- I- uhhh…” You didn’t even have to check to know you looked ridiculous. You twiddled your thumbs and croaked, “I wanted some umm… f-food.”

Your flustered appearance and the small reply made Sans burst into laughter, which calmed you down temporarily. _That was SUCH a lame excuse_ , you scolded to yourself. Your mind finally understood what was going on and you simply lost it trying to come up with excuses. You liked the music he was playing, you wanted to talk to someone, you had been fucking yourself to the sound of his voice for days. Okay, you didn’t say the last one but you sure as hell wanted to. Strange that there was no tension from his end, no anger or shame in his eye. If someone caught you fondling yourself, it would be a totally different story.

In the blink of an eye (literally), you were pinned to the wall by Sans. There was a hunger in the way he scanned you; a craving. You better not be fucking dreaming.

“Kid, do you know how long I’ve wanted this? How long I’ve wanted _you_?” Sans’ voice dropped to a whisper in your ear, turning you on more. “I’ve been aching for ya to tug this bone.”

It came to your attention that his shorts were glowing, specifically the part where a penis is suppose to be. You were dead set on telling yourself this was a dream and it wasn’t happening. Sans would never go this far, would he?

His phalanges teased at the waistline of your pants, causing you to squeak. Although Sans wasn’t nearly as tall compared to his brother, he made you feel very tiny. Very… little. He even appeared to have grown a foot or two since you were in the room; he essentially towered over you now. How the fuck…  
You didn’t know what to do with your limbs, whether to pull him closer, finger his exposed ribcage, or wrap your arms around yourself in defense.

Sans breathed hot air down your neck as he seemed to know what you thought, tacking your arms over your head with his right one. His teeth gently graze your clavicle as he hissed, “I’ve wanted to _fuck_ that soft little cunt of yours.” You were oozing with horniness out every pour. “Claim you…”

He trailed off into blind lust of compressing his grip on your wrists, letting his fingers roam into your pants and travel to your ass, squeezing the lushness, and licking your neck with a warm, slimy tongue. A tongue?! Your eyes darted to his open jaw and low and behold, another cerulean colored appendage was radiating from him. This skeleton never ceased to amaze you.

“You taste so fucking good.”

Pathetic moans were escaping your throat as Sans nibbled on the flesh of your shoulder, your hips swaying back and forth in voracious search for relief of being untouched. The fingers roaming understood your motions and ghosted over your panty line, crawling behind the fabric to discover your folds. You yelped in surprise and bit your lip, two distal phalanges curling deeper into the slit and finally touching the sensitive bead. His fingers were a little cold but welcoming and agreeably gratifying. They were an odd sensation but you loved every second that they circled your clit, earning eager whines from you. By now, you were sure you were red as a beet.

“You like that, baby girl?” You nodded, the nickname sending you into a spasm of wiggling and silent cries. He stopped circling the bud immediately, lifting his head to leer at you. Here you were standing weak kneed, bug eyed, under the mercy of a skeleton flicking your bean. If you hadn’t been so turned on, the look he gave you might’ve scared you but all the same paralyzed you in place.

Your surroundings disappeared again then reappeared in a split second and you found yourself laying on your back beside Sans. That damn grin widened as his eye studied your every curve, his fingers tracing the skin of your stomach, pulling your shirt up. Your face heated only slightly since you were getting more comfortable with him. You had to remind yourself this was _Sans_. He was the one that took you in when there was nowhere else to turn. He was the one that listened to your every problem and offered his opinion if you needed it. He was the one that told you terrible puns to cheer you up in your depression. He was the one that saved your life when you laid on the bathroom floor, sobbing your fucking eyes out with blood gushing all over the place from your wrists and legs. Now here he was, praising your body with such a passion.

“Have I ever told you how much I love your skin? It’s so warm and smooth. Any skeleton would die to have this.” He glanced up to your eyes, suddenly serious. “For once, no pun intended.”

It warmed your heart to see him melt in front of you, let alone confess all of this. You’d been quiet the whole time throughout the ordeal. You guessed because it was so much to take in all at once. One minute you’re watching him masturbate, the next you’re pinned against the wall with him exploring you, and now he’s just enjoying your company. This state was completely different than a few seconds ago. Did you say something wrong? Did he think there was too much at one time? 

Sans must’ve saw the questioned look on your face because he asked you what was wrong and almost instantaneously radiated fear.  
“How do you like me? How am I so special? Couldn’t you find someone better than a fat piece of shit like me?” The white pinpricks came back in his eye sockets, an abrupt sadness flaring in them. The harmonious smile faded into a frown hearing you say that. Sans lifted a hand and brought it to your face, stroking your cheek then running his thumb over your bottom lip, speaking in a soft whisper.

“Don’t say that about yourself. Do you think I’d let you sit there and watch if I didn’t like you? Do you think I’d let you lay beside me on my bed if I didn’t want you to feel wanted? You’re beautiful, princess.” Your heart distended as he spoke, every negative emotion faltering. You’d never heard someone speak to you that sweet before and it nearly brought tears to your eyes. “Sshhh, don’t cry, kitten. Daddy’s here."

How did he know you loved that kink? Jesus, he must listen to you. Your face was blistering as you squeezed your legs shut, squeaking softly. Sans appeared to take enjoyment in your amorous state and wiggles, tilting his head and shooting you a hungry smile.

"Daddy didn't tell you to move." He whispered into your right ear, hot breath lingering over your clavicle, letting out a subtle whimper in return. Now you see why he stopped pinning you. Sans allowed his fingers to crawl up to your breasts, gently squeezing and releasing as your noises got louder. His phalanges confined your left nipple tenderly as you stared at the confused and intrigued look on his face like he had never touched one before, which was quite adorable.

Sans continued with the nipple play before pulling your shirt up inch by inch, looking at you for confirmation. You nodded as a reply as your t-shirt was withdrawn from your body, leaving your chest exposed for him. It was late at night so you didn't put on a bra. His eyesockets gave the impression of widening while his brow furrowed as if trying to concentrate. You smirked down at the skeleton.

"They're so... plump a-and smooth..." He whispered, his skull nearing the tissue and the ecto-tongue slithering out it's prison, coating your nipple in cerulean embellishments. You gasped at the sudden warmness and vibrations his tongue released, pulling the balled up blanket closer to you. You felt a tug on your pants and your grin grew wider, compelling yourself to not move.

"Please-" You whimpered softly, earning the liberation of your pants. Sans took his time with your panties, however, rolling his thumb over the details engraved in the black lace. He pulled the fabric over your thighs, down your knees and off your feet, throwing them  beside the sock pile.

Sans' teeth gently brushed against the sensitive nub, his right hand grasping your inner thigh and digging his distal phalanges into your flesh. You moaned out breathily as he stroked the skin up and down until he found your folds again, dipping a single digit in the slit.

His elbow nudged your thigh to move it and you obeyed the command as he circled your clit in a counterclockwise fashion. You almost felt bad that you weren't returning him the favor of mural masturbation. Almost. His cock seemed to be doing okay on its own, glistening within the bowels of the shorts, that and you couldn't move your arms due to his magic stapling them to the wall. Sans licked your nipple and caressed your bead before stopping once again to your displeasure, smiling at you then winking. You, of course, were flustered at the gesture. Damn you wanted those fingers or his cock inside you.

He got up, walking toward his dresser and pulled out a pastel pink, jingling collar, black thigh highs with a pentagram garter, and a white ball gag from one of the drawers. You almost came just looking at the objects. He was waiting for this moment, it seemed.

"You okay with these?" You nodded as he snapped the clip at the back of your head, showing you the collar which read "KITTEN" in gold sparkly letters. It was adorable, pink, and you wondered what it would look like on the skeleton in front of you. Sans wrapped the collar around your throat, fixing the buckle then pulled away to scrutinize you. "You look lovely, princess." You bit your lip while he examined you, an intense and predatory yet sweetness in his eyes.

Your heart skipped a beat when you noticed him pulling the thigh highs up your bare legs then clasped the garters on your thighs. His metacarpals pushed into your hips, kneading the skin. This was driving you mad with arousal but you remained still as much as you could.

"You want Daddy's fingers in you?" A muffled 'mhmm' forced from your throat as he sat on his knees between your legs, phalanges prodding at your entrance. "You better shut your mouth then, you little whore. I don't wanna hear another sound from you until I'm done, kapiche?" His thumb rested on your clit, beginning to massage in circles for the third time tonight. It was sensitive and made your hips buck faintly. One finger shoved into you, thrusting and curving to get a feel for your walls. You saw Sans look intensely into your eyes, awaiting confirmation to continue his exploit, in which you nodded again.

He leaned down to press his teeth to your sternum as a kiss, nibbling modestly at the skin as his finger twisted inside you. You clamped down his finger, thighs contracting as the kiss wandered up to your clavicle. For a monster that had probably never touched someone in this manner, he sure knew how to pleasure a girl. Maybe he _had been_ watching you for some time. The pervert.

You _still_ thought this was a dream after all this time, everything felt surreal and hazy but that was probably because of what Sans was doing to you. His fingers were strange and smooth, sometimes sharp, but it was bewitching the way he made you want to throw your head back and scream. But you wanted to be a good girl and obey, as hard as it was.

Your teeth dug hard into your lip while trying not to make a sound when his tongue snaked over the cartilage on your ear, entering another finger into you and thrusting rougher. Sans let out a small chuckle as your breathing got faster due to your crest becoming imminent. You attempted to squirm and jerk but the only thing that led to was a severe decline in speed and his thumb to hover over your clit.

"Ah, ah, ah, you haven't earned the right to squirm yet." He bit down on your lobe, causing you to whine from the loss of contact. Sans must've let the noise slide since he didn't want to be too rough with you as he didn't know your tolerance. You felt something warm dripping from your ear onto your neck, something liquid-y. The first thought in your mind was that it's his saliva, but the tongue wasn't out, which meant the only other thing could be blood. Or sweat. Maybe sweat. Hopefully blood, but it's probably sweat.

A coil enveloped below your belly button and made your legs get flimsy, warning that your breach is very close. You still didn't want to speak for fear he'd stop, but by god did you ever want to beg for him to keep going. Sans licked your shoulder and lapped whatever the liquid was, revealing blood mixed with his saliva. He must have bit your ear too hard. The tongue slithered back into its confines then came out again as his grin widened along with your eyes, suddenly amazed in the close sight of the appendage; slimy, warm, and long, dripping with saliva. Sans lower his skull to yours, apparently wanting you to suck on his tongue. You opened your jaw for entry and it snaked inside, searching every nook and cranny of your mouth.

Your head lolled back as the tongue slid further down your throat, feeling rumbles and warmth between Sans' chest and yours. You quietly hummed to the rhythm of his SOUL throbbing as your fluids leaked out of you and onto his fingers, causing your face to blister and your body to tense. The orgasm was much less than what you expected but more  You felt him smile and gently retreat from inside you, pressing his hips against your core.

A fire exploded from your chest and seemed to dance with his own flame. Sans wrapped his arms around you and pulled his tongue from your throat, kissing your cheekbone.

"Sans..." You whispered as your arms fell to your sides. It was anomalous the way everything just... fell apart, for lack of a better word. The world around you seemed to die while he lay on top of you, his whole weight pressing into you. His ribs fit perfectly between yours. His hips felt wonderful between your legs. His cheek against yours felt... right. The whole situation felt right. "What's happen-" He pressed a finger to your lips. With half lidded eye sockets.

"It's called SOUL Bonding, princess. Our SOULs are connecting."

You're laying completely exposed under Sans, your legs are wrapped around his hips and body trembling from previous events. Your heart feels like it's fixing to throb out your chest and- no wait. It's literally coming out! You darted your eyes down to see a small green heart emmited from your chest as a bright blue one crawled from Sans' ribcage. They touched each other, his orbiting around yours as if it were his whole world and you return the favor.

As the two SOULs combined, he presses his teeth to your lips and whispers, "I'm all yours now." Your heart flutters and he can now feel it, blushing a bright blue.

The white pinpricks stare into yours as the SOULs retreat back into their rightful form, taking a piece of one another with them. "And you're all mine." You say softly as you nuzzle the bone where his nose would be.

\---------------

You're laying beside Sans as he holds you, your face is buried in his scapula and every so often he strokes your cheek or runs his phalanges through your hair. A slamming door downstairs snapped both of you out of a daydream, telling you his brother was home. You heard bouncing up the stairs and Sans' name being called from a high-pitched, nasally voice.

"SANS, ANSWER ME!" You turned over so your spine was pressed against his ribs, eyeing the door in wait for it to fly open. In less than two seconds, it did.

Papyrus stood in the doorway staring at Sans holding you and nuzzling his nasal bone into your shoulder in a protective way. There was a look of confusion on the younger brother's face and concern etched into his eye sockets. He probably thought Sans was trying to hurt you.

"Hey, bro." Sans said against your skin, nibbling at the soft flesh and dipping his fingers into the spaces between your ribs.

"ARE YOU OKAY, (Y/N)? WHAT ARE YOU WEARING?" You realized the collar and thigh highs were still on as Papyrus walked towards both of you, his non-existent brows furrowing as you nodded in reply. Your cheeks caught fire went he noticed that Sans covered your most intimate parts with his hands, earning odd looks from him.

"WHY DIDN'T YOU TELL ME I COULD HUG THE HUMAN? SHE DOES NOT KNOW HOW GREAT MY HUGS ARE YET!! AND THEY MOST CERTAINLY ARE... EH... GREAT!!" Papyrus trailed off about how great he was and you just laughed, feeling warmness from Sans' bones. He whispered into your ear that you should probably get up before his brother tackles the both of you with hugs, and with his weight it would be nearly suffocating.

\---------------

All three of you went to Grillby's to eat and talk about your new relationship with Sans minus the _extra._ Papyrus took it as a stronger friendship, which it is, but you explained that you felt about Sans how he felt about Mettaton EX. A bright orange hue appeared on his cheekbones at the statent. You sat in Sans' lap with a plush of a pink bear he bought you on the way there, squeezing it with a huge grin on your face.

"I'm glad you finally found someone to like those horrible puns of yours." Grillby commented from behind the counter, cleaning a glass.

"Ah, come on, you gotta admit some of em are-"

 _"DON'T_."

"-humerus." You giggled anyway as almost all the monsters in the bar groaned, a couple snickering. Papyrus fumed and only spurred Sans on as he pulled you closer.

"If you like that, I've got a skele-TON more."

**Author's Note:**

> Sans stops and starts with the foreplay a lot to build the Reader up but I don't mention it and I am very sorry about that.  
> Also, sorry for it being all over the fricking place. I had a plot for the story but it got deleted off my computer so I had to basically go commando. (Heh, sexual jokes)
> 
> Based off of some of the fics I've read on here. I hope you enjoy this as much as I liked writing it haha. It's 4:30 AM now. I probably need to go to sleep.


End file.
